.TH std::ratio_multiply 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::ratio_multiply \- std::ratio_multiply

.SH Synopsis
   Defined in header <ratio>
   template< class R1, class R2 >           \fI(since C++11)\fP
   using ratio_multiply = /* see below */;

   The alias template std::ratio_multiply denotes the result of multiplying two exact
   rational fractions represented by the std::ratio specializations R1 and R2.

   The result is a std::ratio specialization std::ratio<U, V>, such that given Num ==
   R1::num * R2::num and Denom == R1::den * R2::den (computed without arithmetic
   overflow), U is std::ratio<Num, Denom>::num and V is std::ratio<Num, Denom>::den.

.SH Notes

   If U or V is not representable in std::intmax_t, the program is ill-formed. If Num
   or Denom is not representable in std::intmax_t, the program is ill-formed unless the
   implementation yields correct values for U and V.

   The above definition requires that the result of std::ratio_multiply<R1, R2> be
   already reduced to lowest terms; for example, std::ratio_multiply<std::ratio<1, 6>,
   std::ratio<4, 5>> is the same type as std::ratio<2, 15>.

.SH Example


// Run this code

 #include <iostream>
 #include <ratio>

 int main()
 {
     using two_third = std::ratio<2, 3>;
     using one_sixth = std::ratio<1, 6>;
     using product = std::ratio_multiply<two_third, one_sixth>;
     static_assert(std::ratio_equal_v<product, std::ratio<13, 117>>);
     std::cout << "2/3 * 1/6 = " << product::num << '/' << product::den << '\\n';
 }

.SH Output:

 2/3 * 1/6 = 1/9

.SH See also

   ratio_divide divides two ratio objects at compile-time
   \fI(C++11)\fP      (alias template)
